1. Field of the Invention
The present invention relates to a power switchgear to be installed in a sub station or the like.
2. Description of the Related Art
A conventional power switchgear (hereinafter, “a switchgear”) such as one disclosed in Japanese Patent Application Laid-open No. 2001-118474 includes an operation unit and a circuit breaker. The operation unit includes an output shaft to transmit a rotary torque generated by a spring as a driving force charged in advance manually or by a motor. The circuit breaker includes a grounding container filled with an insulating gas, and a stationary contact and a movable contact arranged in the grounding container. The movable contact makes a movement to make contact with the stationary contact. The movable contact is connected to linkage units such as links and levers and a rotary shaft on the grounding container side. The operation unit is accommodated in an operation box that is arranged under the grounding container. With this configuration, a rotary torque transmitted from the output shaft is transmitted to the movable contact through the rotary shaft, the linkage members, and the levers.
In this circuit breaker, outer peripheries of the output shaft and the rotary shaft and corresponding inner peripheries of cylindrical coupling members are gear-shaped or spline-shaped (hereinafter, “a gear shape”). The output shaft is connected to the rotary shaft via the coupling member to operate in conjunction with the rotary shaft.
However, for assemblability, an inner diameter of the coupling member is essentially larger than an outer diameter of the output shaft or the rotary shaft in the switchgear disclosed in Japanese Patent Application Laid-open No. 2001-118474. This causes a clearance between the coupling member and the output shaft or the rotary shaft and leads to delay in mechanical movement or an undesirable rotational angle when rotational motion by the output shaft is transmitted to the rotary shaft. This may adversely affect mechanical properties of the circuit breaker.